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Desa Wirotaman merupakan salah satu desa terdampak bencana gempa bumi yang terjadi pada April 2021 lalu yang berdampak pada runtuhnya beberapa bangunan dan terganggunya sistem distribusi air bersih pada beberapa lokasi. Padahal, banyak ditemukan sumber mata air di Desa ini yang seharusnya dapat memenuhi kebutuhan warganya. Namun fakta nya, perolehan sumber daya air di desa ini masih belum merata seluruhnya. Beberapa wilayah mengalami kendala air bersih sehingga warganya harus berjalan menuju sumber mata air sambil membawa jerigen-jerigen untuk kemudian dibawa ke rumah masing-masing. Untuk itu, tim abdimas melaksanakan pemasangan pompa hidram pada salah satu sumber mata air di lokasi yang sulit mengakses air bersih untuk memperpendek jarak sehingga air lebih mudah diakses oleh warga. Selain itu, dilakukan pula pengukuran GCP dan pengambilan data citra menggunakan drone. Dari kedua pengukuran ini akan didapat peta orthophoto yang dapat dijadikan acuan dalam perencanaan jalur perpipaan karena memuat data elevasi dan koordinat wilayah.

Increasing population in a city is directly proportional to the increasing demand for land for development. This is inversely proportional to the water catchment area which is decreasing due to land conversion. The water that was supposed to come through the ground turned into a surface stream and overloaded the urban drainage channels. This study analyzes the travel time value (Tc) of the build-up area which will be compared with the peak time value (Tp) in the persiil drainage flow. Results of these Tc and Tp calculation values are then combined to create a linear equation of the influence of watershed characteristics with the large change of land across the city of Surabaya. The linear equations formula analyzed in each district indicate different values. This is due to the influence of differences in the slope of topography and watershed area on each district in Surabaya. The channel scattered throughout the city has different and separate drainage systems from one another depending on the location of its district. This then becomes a consideration to form a formulation of development requirements regarding the relationship of the area of the build-up area with the peak time and volume of the reservoir based on the characteristics of each in order to minimize the flood.

Lately, plastic waste has become a problem in our society, due to the negative impact that it has on our environment. To mitigate this, the reuse of plastic bottle wastes and other local materials should be encouraged. In this paper, the authors present an innovative application for polyethylene terephthalate (PET) that is obtained from plastic bottle wastes, as an additive to Asphalt Concrete-Wearing Course (AC-WC), a hot mix asphalt (HMA) type. The AC-WC sample that contained the PET was measured using the wet method to determine the Marshall parameters of the samples. The type of bitumen used as the specimen is asphalt, which has a penetration value of 60/70. The optimum asphalt content (OAC) obtained from the preliminary study was found to be 5.7% of the total asphalt weight. The results show that AC-WC mixture strength improves when plastic bottle waste is used, which can be correlated with an increase in stability. This finding shows that plastic bottle waste and other local materials have an alternate use as a road pavement material.

The aim of this research is mainly to analyze the influence of adding polyethylene terephthalate (PET) plastic bottle waste to asphalt concrete-binder course mix. The polyethylene terephthalate (PET) plastic bottle waste was added to asphalt concrete-binder course mix using the wet processing method, in which the PET particles were directly mixed with the asphalt hot mix along with its aggregates. This whole research was conducted using asphalt with 60/70 penetration specification and 5.8% of asphalt content. While PET particles were added using various content ratios of 0, 1, 2, 3, 4, 5, 6, 7, and 8%. Based on the Marshall test, it is proven that the number of void in mix (VIM), viscosity modifying admixtures (VMA), and Marshall Quotient went up as the number of density, voids filled with asphalt (VFA), and Marshall flow went down.

Endo-β-1,3-glucanase from alkalophilic bacterium, Bacillus lehensis G1 (Blg32) composed of 284 amino acids with a predicted molecular mass of 31.6 kDa is expressed in Escherichia coli and purified to homogeneity. Herein, Blg32 characteristics, substrates and product specificity as well as structural traits that might be involved in the production of sugar molecules are analysed. This enzyme functions optimally at the temperature of 70 °C, pH value of 8.0 with its catalytic activity strongly enhanced by Mn2+. Remarkably, the purified enzyme is highly stable in high temperature and alkaline conditions. It exhibits the highest activity on laminarin (376.73 U/mg) followed by curdlan and yeast β-glucan. Blg32 activity increased by 62% towards soluble substrate (laminarin) compared to insoluble substrate (curdlan). Hydrolytic products of laminarin were oligosaccharides with degree of polymerisation (DP) of 1 to 5 with the main product being laminaritriose (DP3). This suggests that the active site of Blg32 could recognise up to five glucose units. High concentration of Blg32 mainly produces glucose whilst low concentration of Blg32 yields oligosaccharides with different DP (predominantly DP3). A theoretical structural model of Blg32 was constructed and structural analysis revealed that Trp156 is involved in multiple hydrophobic stacking interactions. The amino acid was predicted to participate in substrate recognition and binding. It was also exhibited that catalytic groove of Blg32 has a narrow angle, thus limiting the substrate binding reaction. All these properties and knowledge of the subsites are suggested to be related to the possible mode of action of how Blg32 produces glucooligosaccharides.

Kata kunci: Polyethylene Terephthalate, AC-BC, Karakteristik Marshall, Temperatur Pemadatan Abstrak Makalah ini bertujuan memberikan analisa pengaruh variasi temperatur pemadatan Campuran Laston Lapis Antara (AC-BC) dengan menggunakan aspal modifikasi yang memanfaatkan limbah plastik jenis Polyethylene Terephthalate (PET). Variasi temperatur pemadatan yang digunakan yaitu 100°C - 180°C dengan interval temperature 100C. Metode yang digunakan dalam pencampuran AC-BC ini adalah metode basah. Pembuatan dan pengujian benda uji dilakukan dalam 2 tahap, yakni pembuatan benda uji tanpa penambahan dan dengan penambahan PET. Hasilnya menunjukkan bahwa temperatur optimum pemadatan aspal konvensional 160°C dan stabilitas 1602,10 kN dan MQ sebesar 376,71 kg/mm. Pada aspal modifikasi dengan penambahan plastik tipe PET didapatkan temperatur optimum pemadatan 180°C dengan nilai stabilitas 2547,27 kN dan MQ sebesar 629,91 kg/mm.

Pada paper ini dibahas efek variasi suhu pemadatan terhadap karaktersitik Marshall pada Campuran Laston Lapis Pondasi (AC-Base) dengan Penambahan Limbah Plastik, jenis Polyethylene Terephthalate (PET) . Metode pencampuran limbah plastik PET digunakan metode basah. Variasi suhu pemadatan antara 100°C-180°C dengan kenaikan setiap 10°C. Penelitian ini mengacu pada spesifikasi umum Kementrian Pekerjaan Umum Bina Marga Revisi III tahun 2010. Hasilnya menunjukkan bahwa nilai kepadatan, VFA ( Void Filled with Asphalt ), Stabilitas, dan MQ ( Marshall Quotient ) semakin meningkat seiring dengan peningkatan suhu pemadatan, baik pada AC-Base tanpa dan dengan penambahan plastik PET. Sebaliknya, nilai VIM ( Void in Mix ), VMA ( Void in Mineral Agreggate ), dan Flow menurun seiring dengan peningkatan suhu pemadatan. AC-Base tanpa penambahan plastik PET memiliki nilai kepadatan, VFA, dan flow yang lebih tinggi dibanding AC-Base dengan penambahan plastik PET, sedangkan untuk nilai VIM, VMA, dan stabilitas lebih rendah.

This paper deals with the innovation of road construction materials by the use of polyethylene terephthalate (PET) as asphalt mixtures. The PET was obtained from plastic bottles waste. The purpose of this research is to investigate the effects of the PET on Marshall parameters on asphalt concrete pavement. The wet method is used in this research. It means that PET plastic material is directly mixed into asphalt when the asphalt is heated, then aggregates are added. In this research, asphalt with penetration of 60/70 is used. Its optimum asphalt content (OAC) is 5.7 percent while The percentages of the added PET are 3 percent, 4 percent, 5 percent, 6 percent, and 7 percent of the asphalt by weight. The results show that the addition of PET plastic waste into the mixture has a significant positive effect on the Marshall parameters of asphalt concrete pavement. The addition of PET waste has been able to increase the value of other Marshall parameters, including Voids in Mix (VIM), Voids in Mineral Aggregates (VMA), Voids Filled with Asphalt (VFA), Flow, and Marshall Quotient (MQ). This research result will contribute to a significant outcome in emerging a sustainable material for road infrastructure.

This paper studies the effect of compaction temperatures on Marshall properties on a Hot Rolled Sheet-Base (HRS-Base) mixture with the addition of plastic waste. Polyethylene terephthalate (PET) type plastic waste from plastic bottle waste is used in this study as an additional material of HRS-Base mixture. The ‘wet method’ is used to mix the PET into HRS-Base mixture, in which the PET is pre-mixed with asphalt material at the temperatures between 160 °C to 170 °C to create modified asphalt before it is mixed with HRS-Base aggregates. The materials used in this study consist of PET from plastic bottle waste, 60/70 penetration asphalt, Portland cement, and aggregates. The aggregate composition used must meet HRS-Base specifications based on the Indonesian National Standard (SNI). The results showed that increasing the compaction temperature of the HRS-Base mixture had an impact on increasing density, Voids Filled with Asphalt (VFA), Marshall stability, and Marshall Quotient (MQ), while the values of Voids in Mix (VIM), Voids in Mineral Aggregates (VMA), and Flow decreased. In addition, HRS-Base without the addition of PET plastic (conventional HRS-Base) and HRS-Base with the addition of PET plastic (modified HRS-Base) were compared. Conventional HRS-Base has a density value, Voids Filled with Asphalt (VFA), and Flow higher than those of modified HRS-Base. While, the value of Voids in Mix (VIM), Voids in Mineral Aggregates (VMA), and Marshall stability of conventional HRS-Base are lower than those of modified HRS-Base.

Study on water balance in a small island is essential to be conducted. A small island normally has small catchment areas so that most of the surface rain water flows quickly into the sea. Consequently, it causes limited recharge of rainwater into groundwater. When the usage of groundwater is high, the water demand-supply could be unbalance. It will certainly cause problems, such as seawater intrusion or water crisis. There are numbers of small islands in Indonesia; in most of these islands, the water balance has not been studied yet. This paper discusses water balance in Poteran- a small island in East Java, Indonesia. The island area is only 49.8 km 2 with population of nearly 50,000 people. The land use in the island is dominated by agricultural areas. In this study, some investigations are conducted including survey of land-surface area, collecting meteorology and climatology data. Thornthwaite approach is used for computing evapotranspiration in water balanced calculation. The results show soil texture dominant is clay loam, with a land use is corn farming (root depth is 0.8 meters), field capacity is estimated 0.25 and permanent wilting point values is 0.12. Precipitation is 1790 mm, the potential evapotranspiration is 2047 mm, water surplus is 300 mm and water deficit is 557 mm a year. The results suggest that the Poteran Island has limited recharge water that could be lead to a water crisis in the future.

This study presents results of numerical back analysis for estimation of strength and modulus parameters of gravelly cobble deposit through various laboratory and field tests. A non-linear and stress dependent stiffness soil model implemented in the finite element software was used to simulate four conventional triaxial compressive (CTS) tests, two pure shear triaxial (PS) tests, one field plate load (PL) test, one field direct shear (FDS) test, and one natural slope stability (NSL) analysis. The internal friction angle ϕ and stress dependent stiffness modulus E50ref back analyzed from those various tests were summarized and evaluated considering the load conditions and stress states. Results show that the strength parameter ϕ tends to decrease linearly with an increase of the minor principal stress σ3′ when they were plotted in a semi-logarithmic graph. The stiffness moduli evaluated from the back analysis, cyclic triaxial test, and downhole test are compared and discussed. In addition, results of numerical analysis of the recent excavation case history in Taichung gravelly cobble deposit are presented to verify the summarized parameters, which are selected with respect to the in-situ stress state.

This study back analyzed deformation parameters of in situ sand through two excavation case histories in Kaohsiung, Taiwan. Two main features are highlighted; deformation prediction based on monitoring data at the first excavation stage and in situ Young’s modulus evaluation for sand considering monitoring data at the overall excavation stages. The former tends to establish a reliable method to predict the wall deflection at the critical stage based on the data at the first stage and the latter to enrich the limited database of Young’s modulus correlation for sand, specifically applicable for deep excavations analysis. The two constitutive models, linear elastic perfectly plastic and non-linear stress–strain constitutive models, were selected. The stiffness parameters of the models were discretely distributed along the subdivided soil body mesh to reflect the effect of overburden pressure on the in situ soil. In addition, relationship between Standard Penetration Test value (SPT-N value) and Young’s modulus and relationships for estimating the in situ Young’s modulus of the Kaohsiung sand as a function of depth were evaluated. The results greatly enhanced a framework for estimating the in situ Young’s modulus of sand.

The feeder bus is needed to support the dedicated infrastructures (i.e. monorail and tram) in order to pick-up passengers from the bus stops in all location to the monorail/tram stations and vice versa. Planning of feeder bus routing is important to be conducted in order to determine the best flow of routes in each of monorail/tram stations. This paper proposes a Genetic Algorithm based approach to develop feeder bus routing model in order to determine the best flow of routes and minimum amount of feeder bus. Surotram project in Surabaya Mass Rapid Transit (SMART) project is selected as the case study in this paper. The results indicated that the base solutions of 12 feeder bus routes were wounded with 45 feeder-bus to serve 51 bus stops in all locations.